Reduction of acids at a platinum ultramicroelectrode: application to “in situ” acid number control of fluid lubricants (phosphate esters)
Résumé
The strength of acids, their charge and possibly their behaviour as polyacids can be deduced by comparing their limiting currents at a platinum ultramicroelectrode in the absence and presence of an excess of supporting electrolyte. Acid-base reactions in tributyl phosphate can be followed without deliberately added supporting electrolyte even if their dielectric constant is low. The acidity of phosphate esters resulting from their hydrolysis can be monitored by amperometry at a platinum ultramicroelectrode.